Washing is increasingly carried out in machines by means of products in the form of powder, granules or in other solid particulate forms. The machines for washing fabrics (hereinafter sometimes referred to as linen) are mainly drum-type machines, but so-called agitator/pulsator machines are also found. Whatever the type of machine employed, the specialists know that the conditions of use of such products are far from ideal. In fact, there is a real problem involved in ensuring a uniform distribution of the particulate product and its dissolving in the washing medium contained in the machine tub. The technical problems regarding powder detergents will be illustrated more particularly hereafter, but it is clear that similar problems arise with detergents taking another form and with any additives having an activity during the washing.
Most of the time, there are machine compartments or containers for receiving the appropriate quantity of powder detergent before the actual washing operation. The powdery active product is thought to be carried into the machine tub by the water as the operation proceeds. However, it has been found that the powder detergent is not carried along completely by the water at all, and therefore more or less large residual quantities remain in the dispensing container. Thus, the intended quantity of powder detergent is not actually used up, and this is detrimental to the efficiency of the washing operation. Furthermore, the containers of the washing machines are always soiled with residues obtained from previous operations. This difficulty is well known and is the subject of many complaints by users.
Another technical problem presented by the use of powder detergents is that the active product does not dissolve completely within the tub, so that the powder which is carried along by the water and which has been unable to dissolve in it in the appropriate way falls directly to the bottom of the tub. Depending on the type of machine, the loss of product in the drainage system can reach 20% of the quantity initially placed in the containers. The undissolved powder is discharged directly into the drainage system of the machine, and in the end this prompts the user to increase the dosage of powder in order to ensure the best possible washing.
To avoid the above-mentioned disadvantages and prevent the losses of detergent in the dispensing containers, some users resort to a rough-and-ready expedient which involves placing the detergent powder directly on the drum of the washing machine, before starting the washing operation. Of course, this measure can be adopted only on a top-opening drum machine, and it too is not without its disadvantages. In fact, although the losses in the dispensing containers may be considered to be eliminated, the same is not true of the losses in the drainage system which are then reduced only slightly. At all events, this solution is not satisfactory because the powder passes through the holes in the drum and comes in direct contact with the fabrics. During the rotation of the drum in the water, the dissolving of the particles of detergent powder which have thus come in contact with the fabrics exerts in adverse influence on this. The detergent particles often have a coloration, and therefore the colored granules of detergent dissolve, thereby releasing the colorant into the fabric itself, and can thus cause stains on this. In the same way, if the detergent composition contains peroxygenated compounds, as is desirable to achieve a high washing performance, the corresponding granules, for example the perborate granules, decompose in contact with the fabric and can discolor articles of delicate color.
There is therefore an undoubted technical problem associated with the fact that the detergents or washing agents present in particulate form do not satisfy the best possible conditions for dissolving in the water during the washing.
To solve such a problem, the present invention employs the concept of a process in which a device is first filled with detergent and is subsequently placed in the machine together with the fabrics to be washed. This concept has been applied to liquid detergents, and a reference which illustrates such a state of the art is French Patent No. 2,563,250 issued Dec. 15, 1986 and entitled: "Process for the machine-washing of linen with a liquid detergent and device for carrying it out". In this case, the detergent contained in the device diffuses progressively into the washing medium and into the fabrics located in the machine. In one embodiment, the device has a filling orifice and vents for the progressive release of the liquid into the linen during the washing.
However, when such a concept is to be applied purely and simply to particulate detergents, in many cases practical difficulties arise. This is because the dissolving of the solid particles of detergent in the washing water is not ensured satisfactorily if such a detergent is placed in a device having orifices, such a device subsequently being introduced into the machine in the middle of the fabrics. In fact, it was found that the presence of orifices on the device, capable of ensuring the diffusion of the detergent, did not allow the powder to dissolve properly. Nor is an increase in the number and/or size of the orifices a satisfactory solution, because it comes up against the same disadvantages as those mentioned at the start of this description, namely the losses of powder in the drainage system and/or contact with the linen when the particles are still solid. It was also found that a reduction in the number and/or dimensions of the orifices results in a progressive locking of the orifices by the wet powder, so that the detergent can no longer escape from the device in order to perform the washing function. The entire discussions set out above therefore shows that, as a general rule, powder detergents cannot be used in the best possible way in dispensing and diffusing devices, even though these prove entirely suitable for liquid detergents.
European Patent Application No. 88/401065.3 published under No. 0290332 on Nov. 9, 1988 proposed using a dispensing and diffusing device containing a detergent in solid form and ensuring that the powder is predissolved before its progressive release into the linen. In one embodiment, such a device comprises a body capable of being filled with the desired quantity of detergent and removable means for closing off this body, the body or the removable means having holes or vents for the release of the detergent. The device is characterized in that it possesses means separating the part of the device having the holes or vents from the part containing the particulate detergent and designed to allow the washing water to pass through freely and practically prevent the massive and uncontrolled escape of the particulate detergent. A structure which has the general shape of a body of revolution closable by means of a removable cap which has holes allowing both the inflow of the water into the device and also the diffusion of the detergent. It is characterized more particularly in that it possesses at least one plate mounted inside the device in order to separate the cap and the part of the body containing the particulate detergent. The plate has at least one orifice, the area of which is less than that of the holes or vents of the cap. Thus, the perforated plate makes it possible to retain the particulate detergent in the body of the device, whilst at the same time allowing the washing water to dissolve this detergent before it is released into the washing machine.
It is an object of the present invention to solve the technical problems mentioned in the above referenced European Patent Application whilst preserving the concept of the progressive diffusion and progressive dispersal of an active product available at the outset in particulate form into the washing medium and into the fabrics ensuring that this product is predissolved before its diffusion. In fact, it is desirable to perfect a dispensing and diffusing device which, whilst preserving a simple structure, makes further improvements to the devices already provided for this purpose with regard to particulate detergents and especially makes it possible to:
reduce the amount of plastic used in the device, this meeting the increasingly important requirements for the protection of the environment, the regulations in this respect being aimed at preventing the disposal of plastic articles which are not normally destroyed in natural surroundings, PA1 obtain a minimum overall size, in order to satisfy the requirements as regards packaging, transport and storage, and PA1 eliminate the noise caused by the dispensing and diffusing devices in the washing machines, in order to satisfy the expectations of some users. PA1 to ensure the filling of the bag with the particulate product, PA1 to prevent the particulate product from escaping from the bag in large quantities in particulate form during the washing, PA1 to make the interior of the bag accessible to the washing medium, in order to ensure the predissolving of the particulate product, the release of the latter thus taking place essentially in the form of a solution passing, at least partially, through the mouth from the inside of the bag towards the outside.
The present invention provides a solution to these technical problems and to others, as will emerge from the following description, whilst at the same time preserving intact the benefits of the dispensing and diffusing devices already provided for particulate detergents, especially those which are the subject of the above mentioned European Patent Application.